Determination of lead in plant tissues: a pitfall due to wet digestion procedures in the presence of sulfuric acid

Abstract

Two wet digestion procedures for the determination of lead in plant materials by electrothermal atomic absorption spectrometry have been evaluated. The combination of HNO₃, H₂O₂ and HF, though leading to incomplete digestion, yielded values corresponding well with the reference or indicative values of the vegetal tissues used. The mixture of H₂SO₄, HNO₃ and HClO₄ gave results that were too low in some instances, owing to the formation of a mixed precipitate (Pb, Ba)SO₄.